GOES-R & JPSS: The Future of Weather Satellites

SPC

All posts tagged SPC

GOES-14 has been out of storage mode and operating in Super Rapid Scan Operations for GOES-R (SRSOR) mode since August 10, providing 1-min imagery. As with past SRSOR data collection periods, the 1-min imagery is available for display in the SPC operational NAWIPS data visualization system. SPC forecasters have been utilizing the imagery in operations when available over relevant areas.

Today (8/18/15) the imagery was especially valuable as GOES-15 (West) underwent a scheduled maneuver, causing a data outage between 1630 and 1759 UTC. More significant to SPC was that GOES-East, to cover for the West outage, operated in Full Disk mode, collecting images only every half hour from 1615 and 1815. This was at a time when convection began to fire ahead and along a cold front passing through an SPC slight risk area across the central US.

The 1-min satellite imagery aided in 2 watch decisions during the early afternoon hours: a severe thunderstorm watch issued at 1815Z over parts of MO/IL, and a tornado watch issued at 1830Z over parts of WI/IA/IL. Cu developing in the clear sky ahead of the front in east-central MO clearly became agitated as a gravity wave feature traversed eastward through 1715Z. Over the next hour, cu quickly evolved into towering cu before eventual initiation took place. Additional development was analyzed further to the north under high clouds near the IA/IL border. Even further north in NE Iowa, strengthening of convection could be seen as bubbling/texture came through a more opaque/smooth cloud shield. Forecasters have commented that the very high temporal restitution satellite imagery allows for easier/more accurate tracking of individual cloud features/structure, especially when partially obscured by upper-level clouds. Evolution of individual features becomes disconnected with longer time between scans, making it difficult to interpret important trend information.

The first animation below shows the 1-min imagery in the time period leading up to and just after initiation during which GOES-East was in Full Disk operations. The second animation shows GOES-East imagery during the same period. SPC watches appear on both. Click animations to enlarge.

The CTC product first signaled cooling of around -10 K/15 min in the IR at 1830 UTC in South Carolina near the Georgia border (Fig. 1), indicating convection was at least trying to develop. Over the next few scans, the product signaled multiple areas of significant growth with increasing intensity over much of the southern half of South Carolina. At 1915 UTC, cooling of over -40 K/15 min was measured with a storm that would be warned on 19 minutes later. Several of the storms would go on to produce severe wind and hail, with the first severe report coming in at 2035 UTC.

The SPC forecaster on the mesoscale desk was monitoring the CTC product over the region, and referenced it in a related Mesoscale Discussion: “THE MODERATE INSTABILITY AND -10 C 500 MB TEMPERATURES ARE PROVING SUFFICIENT FOR RAPID CLOUD TOP COOLING WITH MOST OF THE STORM CELLS IN THIS REGION PER GOES-R CLOUD TOP COOLING PRODUCT” (Fig. 2). The forecaster mentioned that seeing many areas of significant cooling gave him confidence that the environment would be conducive to the development of severe weather. This is a good example of a forecaster using the CTC product output to enhance his understanding of the environment.

GOES-14 has come out of storage and will be providing Super Rapid Scan Operations for GOES-R (SRSOR) 1-min data for the next 2 weeks. Forecasters at SPC have found operational value in this imagery in the past (see previous blog posts), and are once again taking advantage of its availability. Feedback from SPC forecasters is been helpful in assessing the operational utility of 1-min satellite imagery, a capability of the GOES-R Advanced Baseline Imager (ABI) that will be routinely available. For more information, including links to the real-time 1-min imagery and past examples, please visit: http://cimss.ssec.wisc.edu/goes/srsor2014/GOES-14_SRSOR.html.

The GOES-R Overshooting Top (OT) Detection algorithm (applied to current GOES) was utilized during the very early morning hours of June 23 across the Texas panhandle and western Oklahoma. This algorithm, which automatically detects the location of OT’s using the GOES IR window channel, has proven to be especially valuable in monitoring the evolution of mature convection, especially overnight in the absence of the higher resolution visible imagery. As has been mentioned in previous posts, OT’s indicate the presence of strong updrafts within a convective system, and likely areas of hazardous weather. The algorithm provides forecasters with a tool to quickly spot, in the imagery, where OT’s are present as well as trends in the feature.

By 0400Z on the 23rd, an MCS was propagating across the Texas panhandle/western Oklahoma, producing heavy rainfall and severe winds across the region. An SPC forecaster on shift viewing the OT product utilized it to help monitor trends in the strongest updrafts and areas most likely to be experiencing hazardous weather. The forecaster mentions in a 0723Z SPC Watch Update Mesoscale Discussion (MD,Fig. 1): “TRENDS IN 7 KM AND 9 KM CAPPI AND GOES-R OVERSHOOTING TOP PRODUCT INDICATED THE MORE PERSISTENT UPDRAFTS SINCE AT LEAST 0530z HAVE BEEN FROM THE SRN TX PANHANDLE INTO WRN OK…WITH FORWARD MOVEMENT OF THIS ACTIVITY AT 35-40 KT TOWARD THE SSE.”

Figure 2 is an animation of GOES-East IR imagery with overshooting tops and SPC storm reports overlayed during the time of and in the vicinity of the MD. Notice the cluster of persistent Overshooting Tops within the large cloud shield across the Texas panhandle between 0415 and 0530Z. This is where the highest concentration of severe weather (and heavy rainfall) was reported. Between 0530 and 0730 UTC, the MCS continued to propagate to the SSE as the overshooting tops became more spread out along the leading edge of the system from the southern Texas panhandle into western Oklahoma, as was mentioned in the MD. A few wind reports and heavy rainfall were reported in the vicinity of the persistent OT’s. After 1000Z, the OT’s dropped off completely as the MCS began to weaken.

Another example of GOES-14 Super Rapid Scan Operations for GOES-R (SRSOR) 1-minute imagery being utilized in the SPC forecast process comes from May 23 afternoon convection over the Carolinas. A SPC slight risk for severe weather existed along the Carolina coasts, with large hail and damaging winds posing the greatest threat. By 20Z, two SPC severe thunderstorm watches had already been issued for the Carolinas, anticipating severe weather development in the coming hours. The 1-minute imagery was being looked at closely for convective initiation, with a SPC watch update mesoscale discussion issued at 2014Z (Fig. 1). In the text, the forecaster mentions, “1-MIN RESOLUTION VISIBLE SATELLITE IMAGERY AND LIGHTNING STRIKES INDICATE INCIPIENT TSTM DEVELOPMENT OVER MARION/FLORENCE COUNTIES OF SC. ADDITIONAL CLUMPING OF CU HAS BEEN NOTED INTO PARTS OF SERN NC.”

Figure 2 shows GOES-14 1-minute imagery from 1902Z to 2130Z. Notice the significant clumping of cu, as noted in the MD, that occurred between 1900 and 2000Z in northeast South Carolina and eastern North Carolina. Between 2000 and 2130Z, convection initiated out of these two areas, as is seen in the 1-minute imagery.

Fig. 2: May 23, 2014 1902-2130 UTC GOES-14 1-minute visible imagery.

Severe hail was reported with the convection in South Carolina (Fig. 3).

Fig. 3: June 17, 2014 SPC storm reports.

Many SPC forecasters have found the 1-minute imagery to be quite valuable when monitoring for convective initiation as was evident in the case discussed in this post. A few SPC forecaster comments regarding their use of the 1-minute imagery in the pre-storm environment follow:

“The one-minute imagery helped me to anticipate areas of new convective development as well, which was useful in developing short-term forecasts and mesoscale discussions for severe weather. ”

“… having the data available routinely would very likely, over time, allow forecasters to gain a better understanding of processes related to convective initiation, as these processes occurring within a cu field would be visually revealed in high temporal -resolution data in a way that 15- or 30-minute imagery cannot as clearly depict.”

“In the pre-storm environment, these data were especially helpful in monitoring the vertical growth of cumulus convection and in the identification of boundaries.”

“I found it to be very useful in… Using cloud character and trends to diagnose boundary locations and motion, and nowcast their potential for either CI or influences on upshear storms to interact therewith.”

Another example of the utilization of GOES-14 Super Rapid Scan Operations for GOES-R (SRSOR) 1-minute imagery in an Storm Prediction Center (SPC) forecaster’s decision-making process came during the early to mid afternoon hours of May 22, 2014. Severe weather was expected to develop from New York south into eastern Virginia where strong heating and destabilization were expected to occur in the presence of decent deep layer shear. SPC forecasters were interrogating the 1-minute imagery around the Pennsylvania/New York border already by 1549Z, when a Mesoscale Discussion (MD) was issued (Fig. 1). The forecaster mentions in the text that “1-MIN RESOLUTION VISIBLE SATELLITE IMAGERY DEPICTS DEEPENING CU AND SMALL CBS FORMING ALONG/JUST AHEAD OF A COLD FRONT STRETCHING FROM AROUND 25 S ROC TO ZZV.”

A severe thunderstorm watch was issued for much of eastern New York and eastern Pennsylvania at 1640Z anticipating the development of severe convection out of the growing cu field. At 1719 UTC, a watch update MD was issued for the watch area (Fig. 2), noting: “AREAS OF CLUMPING CU EVIDENT IN 1-MIN RESOLUTION VISIBLE IMAGERY FROM S-CNTTRL PA TO CNTRL VA SHOULD EVOLVE INTO ISOLATED TO SCATTERED STORMS BY 19-20Z.”

Figure 3 shows a 3 hour animation of the 1-min visible imagery in the region of concern. Note the deepening cu field and eventual clumping of cu across northern PA into southern New York between 15 and 17Z as mentioned in the two MD’s, followed by the eventual growth of robust convection between 17 and 18Z.

Convection would continue to grow upscale out of this cu field, primarily producing widespread severe hail across the region, with the first report coming in at 1722Z (Fig. 4).

Fig. 4: SPC storm reports for May 22, 2014.

A SPC forecaster commented on the use of the 1-min imagery in operations during this event: “This has provided extra confidence and lead time for the issuance of two mesoscale discussions compared to the normal satellite update frequency/latency. With weakly forced, nebulous low-level boundaries over the Northeast today, the ability to see where boundary layer cumulus is deepening and clumping in this manner is quite striking. It’s analogous to the difference between watching high-def TVs vs. standard def, especially noticeable when switching back and forth to the normal GOES imagery.”

The forecaster went on to mention that “Satellite imagery at 1-min temporal resolution needs to become the new standard for severe weather operations.”

The Cloud Top Cooling (CTC) product was utilized by an SPC forecaster in monitoring for severe weather development across northern Utah into western Wyoming on Wednesday, May 28 2014. This region is characterized by especially poor radar coverage due to mountain beam-beam blocking and coarsely spaced radars (Fig. 1). For this reason, satellite-based products are especially useful to SPC forecasters in the western third of the the United States. In this particular case, the CTC product was helpful in highlighting when rapid convective development was beginning, as well as where the most rapid development was occurring (Fig. 2). Severe winds were eventually reported with these storms. The CTC product was mentioned in SPC Mesoscale Convective Discussion (MCD) 748 (Fig. 3): “THE GOES-R CLOUD TOP COOLING PRODUCT INDICATED COOLING TOPS OVER SWRN TO WEST-CENTRAL WY AND ONGOING CLOUD TOP COOLING IN NERN UT.”